Due to increased network speeds and router design with current Gargoyle/OpenWRT firmware the router throughput in most cases is limited by CPU performance. To increase router network speed/performance one solution is to disable bandwidth monitor (bwmon).
Note: Beware that disabling bwmon you will lose the ability to monitor/track bandwidth data, which will probably disable Quotas and all bandwidth graphs as well.
SSH into your router and type the following commands
<shell> /etc/init.d/bwmon_gargoyle stop /etc/init.d/bwmon_gargoyle disable </shell>
<shell> /etc/init.d/bwmon_gargoyle enable /etc/init.d/bwmon_gargoyle start </shell>
Note: A Reboot may not be necessary afterward, but it's advised.